To drive a fastener such as a threaded bolt and a nut, an open-ended wrench, a box-ended wrench, a monkey wrench or a socket wrench may be used. A socket wrench kit includes a handle and a set of sockets of various sizes. In operation, the handle is connected to a selected one of the sockets for driving a fastener of a certain size. Thus, a socket wrench kit can be used to drive fasteners of various sizes. A socket wrench kit is lighter and less expensive than a set of open-ended wrenches or box-ended wrenches. The handle of a socket wrench kit often includes a selective one-way driving mechanism. Therefore, a socket wrench kit is more convenient than a monkey wrench.
It is important to mark the sockets of a socket wrench kit to indicate the sizes of the sockets. There has been an attempt to provide plastic collars of different colors on sockets of different sizes. The plastic collars could easily be blurred, damaged or detached from the sockets so that the sockets would be poorly marked or not marked at all.
Alternatively, indented marks may be made in the sockets by pressing. It however requires an expensive machine to execute the pressing. Moreover, the indented marks are unclear on the sockets. This problem will be even worse when the indented marks are filled with dirt and grease after some time of use.
A socket is generally coated after the pressing. The electroplated layer is useful in protecting the socket from rust. The electroplated layer is provided on the socket in and outside the indented mark. That is, the color of the socket in the indented mark is identical to the color of the socket outside the indented mark. The electroplated layer makes the indented marks more unclear.
There has been another attempt to provide manganese phosphate on a socket after the pressing. The manganese phosphate is useful in protecting the socket from rust. The manganese phosphate however makes the socket look black and blur the indented mark.
More methods for providing tools with identification systems can be found in Taiwanese Patent Publication No. 555626 and Taiwanese Patent Application Publication No. 200840683. However, only the colors of silver and black can be provided on the tools, and this is not satisfactory regarding the diversity of trademarks.
Therefore, the present invention is intended to obviate or at least alleviate the problems encountered in prior art.